Fasting serum concentration of apolipoprotein B48 represents residual risks in patients with new-onset and chronic coronary artery disease

The effects of pemafibrate and omega-3 fatty acid ethyl on apoB-48 in dyslipidemic patients treated with statin: A prospective, multicenter, open-label, randomized, parallel group trial in Japan (PROUD48 study)

Background

We compared the lowering effects of pemafibrate and omega-3 fatty acid ethyl on fasting apolipoprotein (apo) B-48 (apoB-48), a marker that reflects postprandial hypertriglyceridemia, which is one of the residual risks for atherosclerotic cardiovascular disease (ASCVD) with statin treatment.

Methods

This prospective, multicenter, open-label, randomized, parallel group trial was conducted at 4 medical institutions between April 2020 and May 2022. A total of 126 ambulatory patients with dyslipidemia receiving statin treatment for more than 4 weeks, aged 20-79 years with fasting triglyceride (TG) levels of ≥177 mg/dl were randomly assigned to 16-week pemafibrate 0.4 mg per day treatment group (PEMA, n = 63) or omega-3 fatty acid ethyl 4 g per day treatment group (OMEGA-3, n = 63). The primary endpoint was the percentage change in fasting apoB-48 from baseline to week 16.

Results

The percentage changes in fasting apoB-48 in PEMA and OMEGA-3 were -50.8% (interquartile range -62.9 to -30.3%) and -17.5% (-38.3 to 15.3%) (P < 0.001), respectively. As the secondary endpoints, the changes in fasting apoB-48 in PEMA and OMEGA-3 were -3.10 μg/ml (-5.63 to -1.87) and -0.90 μg/ml (-2.95 to 0.65) (P < 0.001), respectively. Greater decreases with significant differences in the percentage changes in TG, remnant lipoprotein cholesterol, apoC-III, fasting plasma glucose, alanine aminotransferase, gamma-glutamyl transpeptidase, and alkaline phosphatase were observed in PEMA, compared with OMEGA-3. Greater increases with significant differences in those in high-density lipoprotein (HDL) cholesterol, apoA-I, and apoA-II were observed in PEMA, compared with OMEGA-3. PEMA showed anti-atherosclerotic lipoprotein profiles in gel-permeation high-performance liquid chromatography analyses, compared with OMEGA-3. Although adverse events occurred in 9 of 63 (14.3%) patients in PEMA and 3 of 63 (4.8%) patients in OMEGA-3, no serious adverse events associated with drug were observed in either group.

Conclusions

This is the first randomized trial to compare the lowering effects of pemafibrate and omega-3 fatty acid ethyl on fasting apoB-48. We concluded that pemafibrate was superior to omega-3 fatty acid ethyl in lowering effect of fasting apoB-48. Pemafibrate is expected to reduce the residual risk for ASCVD with statin treatment.

Clinical trial registration

https://rctportal.niph.go.jp/en, identifier jRCTs071200011.

Physiological Bases for the Superiority of Apolipoprotein B Over Low-Density Lipoprotein Cholesterol and Non-High-Density Lipoprotein Cholesterol as a Marker of Cardiovascular Risk

In 2019, the European Society of Cardiology/European Atherosclerosis Society stated that apolipoprotein B (apoB) was a more accurate marker of cardiovascular risk than low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol. Since then, the evidence has continued to mount in favor of apoB. This review explicates the physiological mechanisms responsible for the superiority of apoB as a marker of the cardiovascular risk attributable to the atherogenic apoB lipoprotein particles chylomicron remnants, very low-density lipoprotein, and low-density lipoprotein particles. First, the nature and relative numbers of these different apoB particles will be outlined. This will make clear why low-density lipoprotein particles are almost always the major determinants of cardiovascular risk and why the concentrations of triglycerides and LDL-C may obscure this relation. Next, the mechanisms that govern the number of very low-density lipoprotein and low-density lipoprotein particles will be outlined because, except for dysbetalipoproteinemia, the total number of apoB particles determines cardiovascular risk, Then, the mechanisms that govern the cholesterol mass within very low-density lipoprotein and low-density lipoprotein particles will be reviewed because these are responsible for the discordance between the mass of cholesterol within apoB particles, measured either as LDL-C or non-high-density lipoprotein cholesterol, and the number of apoB particles measured as apoB, which creates the superior predictive power of apoB over LDL-C and non-high-density lipoprotein cholesterol. Finally, the major apoB dyslipoproteinemias will be briefly outlined. Our objective is to provide a physiological framework for health care givers to understand why apoB is a more accurate marker of cardiovascular risk than LDL-C or non-high-density lipoprotein cholesterol.

Hypertriglyceridemia, a causal risk factor for atherosclerosis, and its laboratory assessment

Epidemiological and clinical studies show a causal association between serum triglyceride (TG) level, the number of triglyceride-rich lipoproteins (TRLs) and their remnants, and the increased risk of atherosclerosis and cardiovascular disease (CVD) development. In light of current guidelines for dyslipidemia management, the laboratory parameters reflecting TRL content are recommended as part of the routine lipid analysis process and used for CVD risk assessment, especially in people with hypertriglyceridemia (HTG), diabetes mellitus, obesity and low levels of low-density lipoprotein cholesterol (LDL-C), in which high residual CVD risk is observed. The basic routinely available laboratory parameters related with TRL are serum TG and non-high-density lipoprotein cholesterol (non-HDL-C) levels, but there are also other biomarkers related to TRL metabolism, the determination of which can be helpful in identifying the basis of HTG development or assessing CVD risk or can be the target of pharmacological intervention. In this review, we present the currently available laboratory parameters related to HTG. We summarise their link with TRL metabolism and HTG development, the determination methods as well as their clinical significance, the target values and interpretation of the results in relation to the current dyslipidemia guidelines.

Postprandial Hyperlipidemia: Association with Inflammation and Subclinical Atherosclerosis in Patients with Rheumatoid Arthritis

OBJECTIVE

To describe postprandial lipidemia in patients with rheumatoid arthritis (RA) and to analyze its association with subclinical atherosclerosis and inflammatory activity.

METHODS

Observational study of 80 cases of RA and 80 sex- and age-matched controls. We excluded individuals with dyslipidemia. Postprandial hyperlipidemia (PPHL) was defined as postprandial triglycerides >220 mg/dL and/or postprandial ApoB48 levels >75th percentile (>p75). Plasma lipids, cholesterol, triglycerides, ApoB48, and total ApoB were evaluated at baseline and after a meal. Other variables analyzed included subclinical atherosclerosis (defined as presence of carotid atheromatous plaque), inflammatory activity (disease activity score (DAS28-ESR)), cytokines, apolipoproteins, and physical activity. A multivariate analysis was performed to identify factors associated with PPHL in patients with RA.

RESULTS

A total of 75 patients with RA and 67 healthy controls fulfilled the inclusion criteria. PPHL was more frequent in patients with RA than controls (No. (%), 29 (38.70) vs. 15 (22.40); p = 0.036), as was subclinical atherosclerosis (No. (%), 22 (30.10) vs. 10 (14.90); p = 0.032). PPHL in patients with RA was associated with subclinical atherosclerosis (OR (95% CI) 4.69 (1.09-12.11); p = 0.037), TNF-α (OR (95% CI) 2.00 (1.00-3.98); p = 0.048), high-sensitivity C-reactive protein (OR (95% CI) 1.10 (1.01-1.19); p = 0.027), and baseline triglycerides (OR (95% CI) 1.02 (1.00-1.04); p = 0.049).

CONCLUSION

PPHL was more frequent in patients with RA than in controls. PPHL in patients with RA was associated with inflammation and subclinical atherosclerosis.

Effects of Virgin Olive Oil and Phenol-Enriched Virgin Olive Oils on Lipoprotein Atherogenicity

The atherogenicity of low-density lipoprotein (LDL) and triglyceride-rich lipoproteins (TRLs) may be more significant than LDL cholesterol levels. Clinical trials which have led to increased high-density lipoprotein (HDL) cholesterol have not always seen reductions in cardiovascular disease (CVD). Furthermore, genetic variants predisposing individuals to high HDL cholesterol are not associated with a lower risk of suffering a coronary event, and therefore HDL functionality is considered to be the most relevant aspect. Virgin olive oil (VOO) is thought to play a protective role against CVD. This review describes the effects of VOO and phenol-enriched VOOs on lipoprotein atherogenicity and HDL atheroprotective properties. The studies have demonstrated a decrease in LDL atherogenicity and an increase in the HDL-mediated macrophage cholesterol efflux capacity, HDL antioxidant activity, and HDL anti-inflammatory characteristics after various VOO interventions. Moreover, the expression of cholesterol efflux-related genes was enhanced after exposure to phenol-enriched VOOs in both post-prandial and sustained trials. Improvements in HDL antioxidant properties were also observed after VOO and phenol-enriched VOO interventions. Furthermore, some studies have demonstrated improved characteristics of TRL atherogenicity under postprandial conditions after VOO intake. Large-scale, long-term randomized clinical trials, and Mendelian analyses which assess the lipoprotein state and properties, are required to confirm these results.

Postprandial Hyperchylomicronemia and Thin-Cap Fibroatheroma in Nonculprit Lesions

Objective- Although postprandial hypertriglyceridemia can be a risk factor for coronary artery disease, the extent of its significance remains unknown. This study aimed to investigate the correlation between the postprandial lipid profiles rigorously estimated with the meal tolerance test and the presence of lipid-rich plaque, such as thin-cap fibroatheroma (TCFA), in the nonculprit lesion. Approach and Results- A total of 30 patients with stable coronary artery disease who underwent a multivessel examination using optical coherence tomography during catheter intervention for the culprit lesion were enrolled. Patients were divided into 2 groups: patients with TCFA (fibrous cap thickness ≤65 µm) in the nonculprit lesion and those without TCFA. Serum remnant-like particle-cholesterol and ApoB-48 (apolipoprotein B-48) levels were measured during the meal tolerance test. The value of remnant-like particle-cholesterol was significantly greater in the TCFA group than in the non-TCFA group ( P=0.045). Although the baseline ApoB-48 level was similar, the increase in the ApoB-48 level was significantly higher in the TCFA group than in the non-TCFA group ( P=0.028). In addition, the baseline apolipoprotein C-III levels was significantly greater in the TCFA group ( P=0.003). These indexes were independent predictors of the presence of TCFA (ΔApoB-48: odds ratio, 1.608; 95% confidence interval, 1.040-2.486; P=0.032; apolipoprotein C-III: odds ratio, 2.581; 95% confidence interval, 1.177-5.661; P=0.018). Conclusions- Postprandial hyperchylomicronemia correlates with the presence of TCFA in the nonculprit lesion and may be a residual risk factor for coronary artery disease.

Triglycerides and triglyceride-rich lipoproteins in the development and progression of atherosclerosis

PURPOSE OF REVIEW

In this review, we intend to show the heterogenicity of the triglyceride group, including the triglyceride-rich lipoproteins and its subparticles, apolipoproteins, and its role in atherogenesis through epidemiological and genetic studies, observing the association of these various components and subclasses with subclinical atherosclerosis and cardiovascular events. Also, we reevaluated the moment of blood collection for the triglyceride measurement and its repercussion in atherosclerosis. Finally, we present the current scenario and new insights about the pharmacologic treatment of hypertriglyceridemia.

RECENT FINDINGS

Recent studies have been observed, a correlation between cardiovascular disease and triglyceride components (as apolipoproteins A-V, C-I, C-III) as well as proteins involved in the metabolism pathway, such as the angiopoietin-like proteins. Also, the triglyceride-rich lipoproteins, also known as remnants, were recently associated with atherogenesis. Another important topic addressed is about nonfasting triglyceride level, which has been postulated as a better predictor of cardiovascular events than fasting collection.

SUMMARY

Regarding hypertriglyceridemia treatment, the drug therapy was updated, as the omega-3 polyunsaturated fatty acids were tested in primary prevention as eicosapentaenoic acid and docosahexaenoic acid combination resulted in no benefit, whereas the administration of icosapent ethyl in secondary prevention and high-risk patients showed a robust decrease of the cardiovascular outcomes.

Fasting apolipoprotein B48 is associated with large artery atherosclerotic stroke: a case-control study

Fasting Apolipoprotein B48 (ApoB48) is reported to be a well surrogate marker for postprandial lipidemia and have been repeatedly associated with cardiovascular disease. However, whether ApoB48 is also a risk factor for ischemic stroke have not been reported. In this study, our object is to explore the relationship between fasting plasma ApoB48 levels and the large artery atherosclerotic (LAA) stroke.A 1:1 age-(±2), gender-matched case-control study was conducted. LAA patients and healthy controls admitted to our center were prospectively recruited. Clinical data were collected and enzyme-linked immunosorbent assay (ELISA) was used to measure the fasting plasma ApoB48 levels.A cohort of 234 LAA stroke patients and 234 controls were enrolled. Fasting plasma ApoB48 levels were significantly higher in LAA stroke patients than in controls (4.76(3.46) vs 4.00(2.4), P < 0.001). Conditional multivariable analyses indicated that fasting ApoB48 levels were associated with LAA stroke (odds ratio: 1.18; 95% confidence interval: 1.04–1.35; P = 0.014).Our study indicates that increased fasting plasma ApoB48 may be a risk factor for LAA stroke.

Hypertriglyceridemia and cardiovascular risk: a cautionary note about metabolic confounding

Triglycerides are the conventional tool to measure VLDLs, whereas LDL cholesterol (LDL-C) is the conventional tool to measure LDLs. Multiple epidemiological studies, including a series of genetically based analyses, have demonstrated that cardiovascular risk is related to triglycerides independently of LDL-C, and this has led to a series of new therapeutic agents designed specifically to reduce plasma triglycerides. The triglyceride hypothesis posits that increased levels of triglycerides increase cardiovascular risk and decreasing plasma triglycerides decreases cardiovascular risk. In this work, we will examine the validity of the triglyceride hypothesis by detailing the biological complexities associated with hypertriglyceridemia, the genetic epidemiological evidence in favor of hypertriglyceridemia, the evidence from the fibrate randomized clinical trials relating triglycerides and clinical outcomes, and the completeness of the evidence from the initial studies of novel mutations and the therapeutic agents based on these mutations that lower triglycerides. Because of the multiple metabolic links between VLDL and LDL, we will try to demonstrate that measuring triglycerides and LDL-C alone are inadequate to document the lipoprotein profile. We will try to demonstrate that apoB must be measured, as well as triglycerides and cholesterol, to have an accurate estimate of lipoprotein status.

Evidence for increased chylomicron remnants in rheumatoid arthritis

BACKGROUND

Levels of apolipoprotein (apo) B48 may be increased in conditions associated with systemic inflammation and increased cardiovascular disease (CVD) risk such as rheumatoid arthritis (RA). We aimed to evaluate apo B48 levels in patients with RA in relation to subclinical atherosclerosis.

METHODS

Patients with RA (without CVD) and controls without RA but with high CVD risk (based on the presence of diabetes mellitus or a history of CVD) and healthy controls were included in this cross-sectional study. Carotid intima-media thickness (cIMT) was measured as a surrogate for vascular damage.

RESULTS

In total, 312 patients with RA, 65 controls with high CVD risk and 36 healthy controls were included. Patients with RA had the highest mean apo B48 (10.00 ± 6.65 mg/L) compared to controls with high CVD risk and healthy controls (8.37 ± 5.16 and 5.22 ± 2.46, P < .001). Triglycerides levels were comparable with controls. In RA, apo B48 correlated positively with triglycerides (r = .645; P < .001) but not with cIMT. However, in RA subjects not using lipid or blood pressure lowering medication, a weak correlation was found with cIMT (r = .157; P = .014). RA patients in the highest apo B48 tertile were more often rheumatoid factor positive and anti-CCP positive compared to the lowest tertile.

CONCLUSION

Rheumatoid arthritis patients have higher levels of apo B48 compared to controls with high CVD risk and healthy controls, with normal levels of triglycerides. This accumulation of atherogenic chylomicron remnants may contribute to the elevated CVD risk in RA patients.

Antihyperlipidaemic effect of triterpenic acid-enriched fraction from Cyclocarya paliurus leaves in hyperlipidaemic rats

CONTEXT

Cyclocarya paliurus (Batal) Iljinskaja (Juglandaceae) is an edible and medicinal plant; the leaves are used in Chinese folkloric medicine to treat dyslipidaemia and diabetes.

OBJECTIVE

This study evaluates the antihyperlipidaemic potential of the triterpenic acid-enriched fraction (TAE) from C. paliurus and the underlying mechanism.

MATERIALS AND METHODS

The hyperlipidaemic rats were induced by high fat diet for 6 weeks. After oral administration of TAE (200 and 400 mg/kg), the neutral fraction (150 and 300 mg/kg) and statin (4 mg/kg) to the hyperlipidaemic rats for 4 weeks, lipid profile and apolipoprotein (apoB48) level in plasma, and the expression levels of apoB48, microsomal triglyceride transfer protein (MTP), phosphorylation of mitogen-activated protein kinase (MAPK) and tumour necrosis factor α (TNF-α) in intestine were examined. The main constituents in the TAE were identified by HPLC-MS.

RESULTS

TAE administration (400 mg/kg) decreased the levels of atherogenic lipids in serum and liver (p < 0.05) and increased serum high-density lipoprotein cholesterol by 19.7%. Furthermore, TAE treatment (200 and 400 mg/kg) decreased plasma apoB48 level by 15.3 and 19.5%, downregulated intestinal apoB48 and MTP expression levels (p < 0.05), and inhibited TNF-α expression by 36.2 and 56.2% and the phosphorylation level of MAPK by 8.8 and 13.2%, respectively. HPLC analysis revealed the presence of pentacyclic- and tetracyclic-triterpene acids in TAE.

CONCLUSION AND DISCUSSION

These findings suggested that TAE possessed antihyperlipidaemic activity partially involved in the inhibitory effect on apoB48 overproduction, which may provide evidence about its potential role in ameliorating dyslipidaemia.

Triterpenoids from Cyclocarya paliurus and their inhibitory effect on the secretion of apoliprotein B48 in Caco-2 cells

Five previously undescribed compounds including two triterpenoid aglycones, 3β,23-dihydroxy-1,12-dioxo-olean-28-oic acid and 3β,23,27-trihydroxy-1-oxo-olean-12-ene-28-oic acid, and three triterpenoid glucosides cyclocarioside L-N, along with 17 known compounds were isolated from a CH₃Cl-soluble extract of the leaves of Cyclocarya paliurus. Two 27-nor-triterpenoid glycosides were isolated from the genus for the first time. Furthermore, the characterized compounds were tested for the inhibitory effects on apoliprotein B48 secretion in Caco-2 cells. Seven triterpenoid aglycones together with four triterpenoid saponins significantly decreased the apoliprotein B48 oversecretion induced by oleic acid in Caco-2 cells.

Triglycerides Revisited to the Serial

This review discusses the role of triglycerides (TGs) in the normal cardiovascular system as well as in the development and clinical manifestation of cardiovascular diseases. Regulation of TGs at the enzymatic and genetic level, in addition to their possible relevance as preclinical and clinical biomarkers, is discussed, culminating with a description of available and emerging treatments. Due to the high complexity of the subject and the vast amount of material in the literature, the objective of this review was not to exhaust the subject, but rather to compile the information to facilitate and improve the understanding of those interested in this topic. The main publications on the topic were sought out, especially those from the last 5 years. The data in the literature still give reason to believe that there is room for doubt regarding the use of TG as disease biomarkers; however, there is increasing evidence for the role of hypertriglyceridemia on the atherosclerotic inflammatory process, cardiovascular outcomes, and mortality.

Postprandial Hyperlipidemia and Remnant Lipoproteins

Fasting hypertriglyceridemia is positively associated with the morbidity of coronary heart disease (CHD), and postprandial (non-fasting) hypertriglyceridemia is also correlated with the risk status for CHD, which is related to the increase in chylomicron (CM) remnant lipoproteins produced from the intestine. CM remnant particles, as well as oxidized low density lipoprotein (LDL) or very low density lipoprotein (VLDL) remnants, are highly atherogenic and act by enhancing systemic inflammation, platelet activation, coagulation, thrombus formation, and macrophage foam cell formation. The cholesterol levels of remnant lipoproteins significantly correlate with small, dense LDL; impaired glucose tolerance (IGT) and CHD prevalence. We have developed an assay of apolipoprotein (apo)B-48 levels to evaluate the accumulation of CM remnants. Fasting apoB-48 levels correlate with the morbidity of postprandial hypertriglyceridemia, obesity, type III hyperlipoproteinemia, the metabolic syndrome, hypothyroidism, chronic kidney disease, and IGT. Fasting apoB-48 levels also correlate with carotid intima-media thickening and CHD prevalence, and a high apoB-48 level is a significant predictor of CHD risk, independent of the fasting TG level. Diet interventions, such as dietary fibers, polyphenols, medium-chain fatty acids, diacylglycerol, and long-chain n-3 polyunsaturated fatty acids (PUFA), ameliorate postprandial hypertriglyceridemia, moreover, drugs for dyslipidemia (n-3 PUFA, statins, fibrates or ezetimibe) and diabetes concerning incretins (dipeptidyl-peptidase IV inhibitor or glucagon like peptide-1 analogue) may improve postprandial hypertriglyceridemia. Since the accumulation of CM remnants correlates to impaired lipid and glucose metabolism and atherosclerotic cardiovascular events, further studies are required to investigate the characteristics, physiological activities, and functions of CM remnants for the development of new interventions to reduce atherogenicity.

Enhanced Impact of Cholesterol Absorption Marker on New Atherosclerotic Lesion Progression After Coronary Intervention During Statin Therapy

Aim: Clinical trials suggest that residual risks remain for coronary artery disease (CAD) during low-density lipoprotein cholesterol (LDL-C) lowering therapy. We aimed to investigate the role of exogenous lipids in the prognosis of CAD after percutaneous coronary intervention (PCI).

Methods: A total of 145 patients with CAD, who underwent elective PCI, and 82 non-CAD (control) patients were enrolled in this study. CAD patients underwent follow-up coronary angiography 6–9 months after PCI, and were classified into three groups: 1) patients who showed in-stent restenosis (ISR) in the original stented segment, 2) patients with other non-target coronary atherosclerotic lesions (de novo), and 3) patients with neither ISR nor a de novo lesion. Biochemical analyses were performed on fasting serum samples at the time of follow-up coronary angiography.

Results: Despite the controlled serum LDL-C levels, CAD patients with statin showed elevated cholesterol absorption marker campesterol/total cholesterol (TC), synthesis marker lathosterol/TC, campesterol/lathosterol ratio, and apolipoprotein B48 (apoB48) concentration compared with non-CAD patients. The high campesterol/TC, campesterol/lathosterol ratio, and apoB48 concentration were associated with de novo lesion progression after PCI. In stepwise multivariate logistic regression analysis, campesterol/TC and apoB48 concentrations were independent risk factors for de novo lesion progression in statin-treated CAD patients after PCI.

Conclusion: The increase of cholesterol absorption marker and apoB48 concentration may lead to the progression of de novo lesions, and these markers may represent a residual risk during statin treatment after PCI.

Effect of Glycemic Control on Chylomicron Metabolism and Correlation between Postprandial Metabolism of Plasma Glucose and Chylomicron in Patients with Type 2 Diabetes Treated with Basal-bolus Insulin Therapy with or without Vildagliptin

Aim: Glucagon-like peptide-1 can reduce both postprandial plasma glucose (PG) and chylomicron (CM) levels in patients with type 2 diabetes. However, there have been no reports regarding the relationship between the postprandial metabolism of PG and CM.

Methods: Patients with type 2 diabetes who were admitted for glycemic control were randomized to insulin alone (Ins; n = 16) or insulin plus vildagliptin 100 mg (InsV; n = 16) groups. The insulin dose was adjusted to maintain normal blood glucose levels. The daily profiles of serum TG, remnant lipoprotein cholesterol (RemL-C), and apolipoprotein B48 (ApoB48) were estimated by frequent blood collection on admission and before discharge, and the daily glucose fluctuation profile was also estimated using continuous glucose monitoring (CGM) before discharge.

Results: The daily profiles of serum TG and RemL-C indicated a significant decrease before discharge compared with on admission; however, no significant changes in serum ApoB48 levels were observed in either group. At discharge, daily glucose fluctuation profile and the change in the serum ApoB48 level from fasting to the peak of the daily profile was significantly smaller in the InsV group than in the Ins group. The increment of serum ApoB48 level was significantly correlated with the mean amplitude of glycemic excursions calculated using CGM data only in the Ins group (R² = 0.5242, P <0.001).

Conclusions: Short-term glycemic control decreased serum TG and RemL-C levels, but not ApoB48 levels, and the postprandial metabolism of PG and CM might be regulated by the same mechanism except GLP-1 effect.

Increased postprandial apolipoprotein B-48 level after a test meal in diabetic patients: A multicenter, cross-sectional study

OBJECTIVE

To evaluate plasma apolipoprotein B (ApoB)-48 concentrations among Korean diabetic subjects with normal to moderately high levels of low-density-lipoprotein cholesterol (LDL-C).

METHODS

This multicenter, cross-sectional study included subjects with LDL-C levels between 100 and 160mg/dL who had not been treated with a lipid-lowering agent for over 6weeks prior to baseline. Blood tests to assess lipid-profile parameters were conducted in both fasting and postprandial states. This study compared ApoB-48 and other lipid-profile parameters in diabetic and nondiabetic subjects.

RESULTS

Of the 93 subjects enrolled, 88 (42 diabetic; 46 nondiabetic) completed the study. Significantly higher mean incremental area under curve (0-6h; iAUC0-6h) of postprandial ApoB-48 levels was noted among diabetic subjects than nondiabetic subjects (p=0.0078). The mean postprandial ApoB-48 peak level was higher in diabetic subjects; however, the difference was not statistically significant. The fasting ApoB-48 level was similar in both groups: 5.9 (3.5) in diabetics and 7.3 (5.8) in nondiabetics (p=0.18). The iAUC0-6h of postprandial total cholesterol (TC), triglyceride (TG), LDL-C, non-high-density-lipoprotein cholesterol (non-HDL-C), ApoB-100, and remnant cholesterol was similar in both groups. The ApoB-48 level was moderately correlated with TG and non-HDL-C for both groups (p<0.05).

CONCLUSION

Without lipid-lowering treatment, the postprandial increment in ApoB-48 level was significantly higher in Korean diabetic subjects compared with nondiabetic subjects, irrespective of similar LDL-C levels.

Effect of Pitavastatin Treatment on ApoB-48 and Lp-PLA₂ in Patients with Metabolic Syndrome: Substudy of PROspective Comparative Clinical Study Evaluating the Efficacy and Safety of PITavastatin in Patients with Metabolic Syndrome

BACKGROUND

Apolipoprotein (Apo) B-48 is an intestinally derived lipoprotein that is expected to be a marker for cardiovascular disease (CVD). Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) is a vascular-specific inflammatory marker and important risk predictor of CVD. The aim of this study was to explore the effect of pitavastatin treatment and life style modification (LSM) on ApoB-48 and Lp-PLA₂ levels in metabolic syndrome (MS) patients at relatively low risk for CVD, as a sub-analysis of a previous multi-center prospective study.

METHODS

We enrolled 75 patients with MS from the PROPIT study and randomized them into two treatment groups: 2 mg pitavastatin daily+intensive LSM or intensive LSM only. We measured the change of lipid profiles, ApoB-48 and Lp-PLA₂ for 48 weeks.

RESULTS

Total cholesterol, low density lipoprotein cholesterol, non-high density lipoprotein cholesterol, and ApoB-100/A1 ratio were significantly improved in the pitavastatin+LSM group compared to the LSM only group (P≤0.001). Pitavastatin+LSM did not change the level of ApoB-48 in subjects overall, but the level of ApoB-48 was significantly lower in the higher mean baseline value group of ApoB-48. The change in Lp-PLA₂ was not significant after intervention in either group after treatment with pitavastatin for 1 year.

CONCLUSION

Pitavastatin treatment and LSM significantly improved lipid profiles, ApoB-100/A1 ratio, and reduced ApoB-48 levels in the higher mean baseline value group of ApoB-48, but did not significantly alter the Lp-PLA₂ levels.

Chylomicrons: Advances in biology, pathology, laboratory testing, and therapeutics

The adequate absorption of lipids is essential for all mammalian species due to their inability to synthesize some essential fatty acids and fat-soluble vitamins. Chylomicrons (CMs) are large, triglyceride-rich lipoproteins that are produced in intestinal enterocytes in response to fat ingestion, which function to transport the ingested lipids to different tissues. In addition to the contribution of CMs to postprandial lipemia, their remnants, the degradation products following lipolysis by lipoprotein lipase, are linked to cardiovascular disease. In this review, we will focus on the structure-function and metabolism of CMs. Second, we will analyze the impact of gene defects reported to affect CM metabolism and, also, the role of CMs in other pathologies, such as atherothrombotic cardiovascular disease and diabetes mellitus. Third, we will provide an overview of the laboratory tests currently used to study CM disorders, and, finally, we will highlight current treatments in diseases affecting CMs.

In vivo evidence for chylomicrons as mediators of postprandial inflammation

BACKGROUND AND AIMS

The postprandial situation is a pro-inflammatory condition most likely linked to the development of atherosclerosis. We evaluated the relationship between apolipoprotein (apo) B48 and fasting and postprandial leukocyte activation markers.

METHODS

Leukocyte activation markers and apo B48 were determined in 80 subjects with and without coronary artery disease (CAD). Twelve healthy subjects underwent an oral fat loading test (up to 8 h).

RESULTS

Fasting apo B48 was significantly higher in patients with CAD (n = 47, 8.1 ± 5.2 mg/L) than in subjects without CAD (n = 33, 5.9 ± 3.9 mg/L, p = 0.022). Fasting apo B48 and triglycerides correlated positively with fasting monocyte CD11b and neutrophil CD66b expression. Plasma apo B48 and leukocyte activation markers increased after an oral fat load. No correlations were found between fasting or postprandial triglycerides and postprandial leukocyte activation markers. We observed no correlations between postprandial apo B48 and postprandial neutrophil CD11b or CD66b expression.

CONCLUSION

This study suggests that chylomicron remnants may be responsible for postprandial leukocyte activation in the circulation. The postprandial chylomicron response may be a stronger mediator of postprandial inflammation than postprandial triglyceridemia.

Metabolic fate of fructose ingested with and without glucose in a mixed meal

Ingestion of pure fructose stimulates de novo lipogenesis and gluconeogenesis. This may however not be relevant to typical nutritional situations, where fructose is invariably ingested with glucose. We therefore assessed the metabolic fate of fructose incorporated in a mixed meal without or with glucose in eight healthy volunteers. Each participant was studied over six hours after the ingestion of liquid meals containing either ¹³C-labelled fructose, unlabeled glucose, lipids and protein (Fr + G) or ¹³C-labelled fructose, lipids and protein, but without glucose (Fr), or protein and lipids alone (ProLip). After Fr + G, plasma ¹³C-glucose production accounted for 19.0% ± 1.5% and ¹³CO2 production for 32.2% ± 1.3% of ¹³C-fructose carbons. After Fr, ¹³C-glucose production (26.5% ± 1.4%) and ¹³CO₂ production (36.6% ± 1.9%) were higher (p < 0.05) than with Fr + G. ¹³C-lactate concentration and very low density lipoprotein VLDL ¹³C-palmitate concentrations increased to the same extent with Fr + G and Fr, while chylomicron ¹³C-palmitate tended to increase more with Fr + G. These data indicate that gluconeogenesis, lactic acid production and both intestinal and hepatic de novo lipogenesis contributed to the disposal of fructose carbons ingested together with a mixed meal. Co-ingestion of glucose decreased fructose oxidation and gluconeogenesis and tended to increase ¹³C-pamitate concentration in gut-derived chylomicrons, but not in hepatic-borne VLDL-triacylglycerol (TG). This trial was approved by clinicaltrial. gov. Identifier is NCT01792089.